Ophthalmologic photographing apparatus

ABSTRACT

An ophthalmologic photographing apparatus includes an optical system, a pedestal, an auxiliary lens configured to be able to be inserted into and retracted from the optical system, a focusing lens, a focusing lens driving unit configured to move the focusing lens along an optical axis, a pedestal position detection unit configured to detect that the pedestal is away from the subject&#39;s eye by a predetermined distance, an auxiliary lens insertion detection unit configured to detect that the auxiliary lens is inserted into the optical system, a storage unit configured to store a position of the focusing lens, and a control unit configured to cause the focusing lens driving unit to move the focusing lens to a predetermined position stored in the storage unit based on outputs from the pedestal position detection unit and the auxiliary lens insertion detection unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ophthalmologic photographingapparatus that is used in an ophthalmic office for observing andphotographing a fundus and an anterior segment of a subject's eye.

2. Description of the Related Art

There has conventionally been known an ophthalmologic photographingapparatus, as discussed in Japanese Patent Application Laid-Open No.6-254054, in which observation of a fundus can be changed to observationof an anterior segment by inserting an auxiliary lens optical systeminto an optical path of an observation/photographing optical systemaccording to the position of a pedestal that can be moved backward andforward and right and left relative to a subject's eye.

In this case, during the observation of the fundus, the pedestal is madeclose to the subject's eye, and the auxiliary lens optical system isretracted to the outside of the optical path to observe and photographthe fundus. On the other hand, during the observation of the anteriorsegment, the pedestal is moved away from the subject's eye and theauxiliary lens optical system is inserted into the optical path toobserve and photograph the anterior segment.

However, in the above ophthalmologic photographing apparatus, a focusinglens is required to be readjusted with the inserting and retractingmovement of the auxiliary lens optical system, when the changeoverbetween the observation/photographing of the fundus and theobservation/photographing of the anterior segment is performed, whichmeans the operation is troublesome.

SUMMARY OF THE INVENTION

The present invention is directed to an ophthalmologic photographingapparatus that does not need to readjust a focusing lens during achangeover of observation and photographing, and that facilitates thechangeover of observation and photographing.

According to an aspect of the present invention, an ophthalmologicphotographing apparatus includes an optical system configured to be usedto observe and photograph a subject's eye, a pedestal configured to movethe optical system backward and forward and right and left relative tothe subject's eye, an auxiliary lens configured to be able to beinserted into and retracted from the optical system, a focusing lensconfigured to focus the optical system on the subject's eye, a focusinglens driving unit configured to move the focusing lens along an opticalaxis, a pedestal position detection unit configured to detect that thepedestal is away from the subject's eye by a predetermined distance, anauxiliary lens insertion detection unit configured to detect that theauxiliary lens is inserted into the optical system, a storage unitconfigured to store a position of the focusing lens, and a control unitconfigured to cause the focusing lens driving unit to move the focusinglens to a predetermined position stored in the storage unit based onoutputs from the pedestal position detection unit and the auxiliary lensinsertion detection unit.

Further features and aspects of the present invention will becomeapparent from the following detailed description of exemplaryembodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate exemplary embodiments, features,and aspects of the invention and, together with the description, serveto explain the principles of the invention.

FIG. 1 is a diagram illustrating a configuration of an ophthalmologicphotographing apparatus according to an exemplary embodiment of thepresent invention.

FIGS. 2A and 2B are front views of a crystalline lens diaphragm.

FIG. 3 is an outer appearance of the ophthalmologic photographingapparatus.

FIG. 4 is a diagram illustrating a configuration of a pedestal positiondetection unit.

FIG. 5 is a flowchart illustrating an operation of observing andphotographing an anterior segment.

FIG. 6 is a flowchart illustrating an operation of observing andphotographing a fundus.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the inventionwill be described in detail below with reference to the drawings.

FIG. 1 illustrates a configuration of an ophthalmologic photographingapparatus configured to observe and photograph a subject's eye. Theophthalmologic photographing apparatus includes an illumination opticalsystem including components from a halogen lamp 1, which serves as anillumination light source for observation, to an objective lens 2.Specifically, arranged to the halogen lamp 1 are a visible-light cutfilter 3, a diffusion plate 4, a xenon tube 5, a lens 6, a pupildiaphragm having an annular opening, a crystalline lens diaphragm 8configured to be able to be inserted to or retracted from an opticalpath and having an annular opening, and a mirror 9. Relay lenses 10 and11, a cornea diaphragm 12 having an annular opening, and a perforatedmirror 13 are sequentially arranged in the reflecting direction of themirror 9. A reflection mirror 14 is provided at the rear of the halogenlamp 1.

In an optical system for observation and photographing at the rear ofthe perforated mirror 13, there are arranged a photographic diaphragm15, a diopter correction lens 16 that can be inserted into or retractedfrom an optical path, and that enlarges a focusing range, an auxiliarylens 17 for enlarging magnification configured to be able to be insertedinto or retracted from the optical path, a focusing lens 18 configuredto move along the optical axis, an imaging lens 19, and an imaging unit20. An auxiliary lens insertion detection unit 21 that detects whetherthe auxiliary lens 17 is inserted into the optical path is provided inthe vicinity of the auxiliary lens 17.

The output of the imaging unit 20 is connected to a control unit 22. Thecontrol unit 22 is connected to the auxiliary lens insertion detectionunit 21, a focusing lens driving unit 23, a monitor 24, a pedestalposition detection unit 25 including a microswitch for detecting theposition of the pedestal, and a photographing switch 26.

During the observation, a light flux emitted from the halogen lamp 1 ismade into infrared light in which light in a visible-light wavelengtharea is cut by the visible light cut filter 3, and the resultant passesthrough the diffusion plate 4, the xenon tube 5, the lens 6, the pupildiaphragm 7, and the crystalline lens diaphragm 8 to be incident on themirror 9. The light flux reflected by the mirror 9 passes through therelay lenses 10 and 11, and the cornea diaphragm 12, reflected on theperforated mirror 13, and then, incident on a not-illustrated subject'seye through the objective lens 2. During the photographing, the visiblecolored light emitted from the xenon tube 5 is incident on the subject'seye through the optical path similar to that of the infrared light.

The light flux reflected on the subject's eye passes through theobjective lens 2, and then, passes through the holes of the perforatedmirror 13 to be imaged on the imaging unit 20 through the photographicdiaphragm 15, the diopter correction lens 16, the auxiliary lens 17, thefocusing lens 18, and the imaging lens 19.

When the mydriasis of the subject's eye is insufficient, the crystallinelens diaphragm 8 illustrated in FIG. 2A can be replaced by a crystallinelens diaphragm 8′ illustrated in FIG. 2B in which a centrallight-shielding portion is decreased to enlarge the area of the openingportion.

FIG. 3 is a diagram illustrating an outer appearance of theophthalmologic photographing apparatus according to the presentexemplary embodiment. A pedestal 32 that can be moved backward andforward and right and left as indicated by arrows is placed on a base31. A main body 33 having incorporated therein the optical system of theophthalmologic photographing apparatus illustrated in FIG. 1 and themonitor 24 are placed on the pedestal 32. The pedestal 32 is providedwith an operation stick 34 having the photographing switch 26 formed onits top. The pedestal position detection unit 25 is mounted between thebase 31 and the pedestal 32.

FIG. 4 is a diagram illustrating a configuration of the pedestalposition detection unit 25. A height difference is formed in thelongitudinal direction on the top surface of the base 31, wherein a lowportion 31 a and a high portion 31 b are formed. The pedestal positiondetection unit 25 mounted on the bottom surface of the pedestal 32 isturned off when it is located above the low portion 31 a of the base 31,while it is turned on when it is located above the high portion 31 b.Specifically, since the low portion 31 a on the bottom surface of thebase 31 is provided at the side of the subject S, while the high portion31 b is provided at the operator side, the position of the pedestal 32can be detected by detecting on/off of the pedestal position detectionunit 25.

FIG. 5 is a flowchart illustrating the operation of observing ananterior segment and photographing the anterior segment. When theoperator observes and photographs the anterior segment of the subject S,the operator firstly operates to allow the main body 33 to be away fromthe subject S with the use of the operation stick 34 and the pedestalposition detection unit 25. In this operation, the respective parts areinitialized by the control unit 22, and then, the distance between thesubject S and the pedestal 32 is confirmed by the pedestal positiondetection unit 25 in step S1, whereby the control unit 22 detects thatthe main body 33 is away from the subject S by a predetermined value ormore. When it is determined that the distance between the subject S andthe pedestal 32 is less than the predetermined value (NO in step S1),the control unit 22 returns the focusing lens 18 to the initial positionor moves the focusing lens 18 to a predetermined position in step S2.

When it is determined that the distance between the subject S and thepedestal 32 is the predetermined value or more (YES in step S1), thecontrol unit 22 determines in step S3 whether the auxiliary lens 17 thatchanges the photographing magnification is inserted into the opticalpath. When the auxiliary lens 17 is detected by the auxiliary lensinsertion detection unit 21, which means that the auxiliary lens 17 isinserted (YES in step S3), the processing proceeds to step S4. When itcannot be detected in step S3 that the auxiliary lens 17 is insertedinto the optical path (NO in step S3), the processing proceeds to stepS2.

When the main body 33 is moved away from the subject S, and theauxiliary lens 17 is inserted into the optical path, the control unit 22detects the position of the focusing lens 18 at this time and stores theposition into a focus position storing unit in the control unit 22.

Next, in step S5, the control unit 22 moves the focusing lens 18 towardthe plus diopter at the side of the auxiliary lens 17 along the opticalpath by the focusing lens driving unit 23, whereby the focusing lens 18is moved in the range where the anterior segment of the subject's eyecan be focused. In step S6, the operator observes and photographs theanterior segment.

The operator performs the above-mentioned operation to observe theanterior segment on the monitor 24. When the anterior segment isphotographed after the observation, the operator confirms that thephotographing range and focusing are satisfactory, and then, operatesthe photographing switch 26 to photograph a still image of the anteriorsegment. The reflectivity of the photographic light is different ingeneral between the anterior segment and the fundus. Therefore, theanterior segment is irradiated with a light quantity corresponding tothe anterior segment.

In the present exemplary embodiment, the optical system is unambiguouslyfixed during the photographing of the anterior segment as describedabove, whereby the photographing magnification is kept constant, whichis suitable for comparing the image to a previous image or measuring theimage.

FIG. 6 is a flowchart illustrating the operation of observing a fundusand photographing the fundus. When the fundus is observed andphotographed, the operator operates to allow the main body 33 to beclose to the subject S by the operation stick 34 and the pedestalposition detection unit 25 after the operator retracts the auxiliarylens 17 from the optical path. In step S11, the control unit 22 confirmsthe position of the pedestal 32 to the subject S. When the distancebetween the subject S and the pedestal is a predetermined value or more(NO in step S11), the control unit 22 moves the focusing lens 18 to theplus diopter side in step S12. When it is determined that the distancebetween the pedestal 32 and the subject is less than the predeterminedvalue (YES in step S11), the control unit 22 determines whether theauxiliary lens 17 is retracted from the optical path in step S13. Whenit is determined that the auxiliary lens 17 is not retracted from theoptical path (NO in step S13), the processing proceeds to step S12.

When it is determined in step S13 that the auxiliary lens 17 isretracted from the optical path (YES in step S13), the processingproceeds to step S14. The control unit 22, which has detected theretraction of the auxiliary lens 17 from the optical path by theauxiliary lens insertion detection unit 21, moves the focusing lens 18to a predetermined position stored in the focus position storing unit instep S14. Then, in step S15, the operator operates the operation stick34, while observing the fundus on the monitor 24, to accurately alignthe position to the subject's eye and perform accurate focusing by thefocusing lens 18. In this way, the operator confirms the photographingrange.

The above-mentioned operation is performed with infrared light, which isemitted from the halogen lamp 1 and from which the visible light is cut.In step S16, the operator observes the image of the fundus on themonitor 24, and confirms that the photographing range and focusing aresatisfactory. Thereafter, the operator operates the photographing switch26 to photograph a still image after allowing the xenon tube 5 to emitlight. In this case, the fundus is irradiated with photographing lighthaving a light quantity suitable for the fundus.

In the present exemplary embodiment, the auxiliary lens 17 is providedin the optical path to be inserted into or retracted from the opticalpath. However, the diopter correction lens 16 that enlarges the focusingrange may also be used as the auxiliary lens 17. The order of thedetection of the position of the main body 33 and the detection of theinsertion state of the auxiliary lens 17 in the flowcharts in FIGS. 5and 6 is not limited to the one in the flowcharts in FIGS. 5 and 6. Thedetection of the insertion state of the auxiliary lens 17 may beexecuted first.

The quantity of light during the changeover between the observation ofthe anterior segment and the observation of the fundus may be set bycontrolling a quantity of emitted light from the light source, or may beset in conjunction with the changeover between the crystallite lensdiaphragm 8 illustrated in FIG. 2A and the crystallite lens diaphragm 8′illustrated in FIG. 2B.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications, equivalent structures, and functions.

This application claims priority from Japanese Patent Application No.2009-199969 filed Aug. 31, 2009, which is hereby incorporated byreference herein in its entirety.

1. An ophthalmologic photographing apparatus comprising: an opticalsystem configured to observe and photograph a subject's eye; a pedestalconfigured to move the optical system backward and forward and right andleft relative to the subject's eye; an auxiliary lens configured to beable to be inserted into and retracted from the optical system; afocusing lens configured to focus the optical system on the subject'seye; a focusing lens driving unit configured to move the focusing lensalong an optical axis; a pedestal position detection unit configured todetect that the pedestal is away from the subject's eye by apredetermined distance; an auxiliary lens insertion detection unitconfigured to detect that the auxiliary lens is inserted into theoptical system; a storage unit configured to store a position of thefocusing lens; and a control unit configured to cause the focusing lensdriving unit to move the focusing lens to a predetermined positionstored in the storage unit based on outputs from the pedestal positiondetection unit and the auxiliary lens insertion detection unit.
 2. Theophthalmologic photographing apparatus according to claim 1, wherein theauxiliary lens is also used as a diopter correction lens configured toenlarge a focusing range of the optical system.
 3. The ophthalmologicphotographing apparatus according to claim 1, wherein the predeterminedposition of the focusing lens is at a plus diopter side of the focusinglens.
 4. The ophthalmologic photographing apparatus according to claim1, wherein the control unit changes a quantity of light in conjunctionwith a changeover between photographing of a fundus and photographing ofan anterior segment.
 5. The ophthalmologic photographing apparatusaccording to claim 1, further comprising a crystalline lens diaphragmprovided in an illumination optical system and having an opening portionthat can vary in area in conjunction with a changeover betweenphotographing of a fundus and photographing of an anterior segment.